An Optically Transparent Hybrid Mechanism Metasurface for Wideband, Wide-Angle and Omnidirectional Scattering Suppression

Metasurface provides an efficient method to regulate wave propagation in multiphysics fields ranging from light waves, electromagnetic (EM) waves, and acoustic waves. Considering the versatile demands in practical scenarios, the essential challenge is to design the metasurface with spectral compatibility to satisfy the various applications. Here, we proposed an optically transparent hybrid mechanism metasurface (HMM) incorporating absorption, polarization conversion, and phase cancellation mechanisms for wideband, wide-angle, and omnidirectional scattering suppression performance. The unit cell integrates absorption and polarization conversion capabilities by etching the indium tin oxide (ITO) film into the specific structure, exhibiting wideband ( $7.44-31.31$ GHz), wide-angle ( $\!< 45^{\circ }$ ), high-efficiency ( $\!\ge 90$ %), and omnidirectional co-polarized scattering suppression performance. Moreover, the phase cancellation mechanism is implemented by distributing the unit cell and its mirror structure in the chessboard configuration, which provides cross-polarized reflection reduction capability for the HMM. Therefore, the HMM achieves a significant total radar cross section (RCS) reduction by integrating multiple scattering suppression mechanisms. Eventually, the simulated and measured results indicate that the proposed HMM can realize more than 10 dB total monostatic and bistatic RCS reduction within 7.49-32.23 and 7.46-30.55 GHz, respectively. In addition, good specular and omnidirectional RCS reduction capabilities are also obtained. Furthermore, the HMM also presents good optical transparency, which is attributed to the high transmittance of the polyethylene terephthalate (PET) substrates and the ITO films. The proposed strategy has potential application in the multifunctional stealth design of stealth platforms.